Solution and solid state nuclear magnetic resonance (NMR) spectroscopy are being used along with circular dichroism spectropolarimetry, microelectrophoretic mobility, fluorescence spectroscopy, differential scanning calorimetry, mass spectrometry, low angle neutron scattering and computer modelling to study the structure of peptides and small proteins. Currently complete is the NK-2 homeodomain encoded from the homeobox gene of Drosophila melanogaster in the free and DNA bound state. Studies are also in progress on an antigenic peptide bound to an antiprotein monoclonal antibody. The structure of a peptide fragment from the 828- 848 region of gp41 bound to micelles and also to model membrane surfaces is currently under investigation.